<?php
$a=123;
$b=$a;
$b=456;
echo $a,"\t",$b,"\n";
$a=['name'=>'张三','age'=>22];
$b=$a;
$b['age']=18;
print_r($a);
print_r($b);
$a=123;
$b=&$a;
$b=567;
echo $a,"\t",$b,"\n";
$a=['name'=>'张三','age'=>22];
$b=&$a;
$b['name']='李四';
$b['age']=18;
print_r($a);
print_r($b);
function f(string &$name){
    $name = $name . '丰'; // 拼接字符串
}
$xm='张三';
f($xm);
echo $xm,"\n";